Abstract
The organization of collagen fibers and fibrils on the alveolar bone side in the periodontal ligament of rat molars was observed by scanning electron microscopy after maceration of the cellular elements by sodium hydroxide (NaOH) treatment. Two types of periodontal ligament-to-alveolar bone attach-ments were distinguished. Type A: thick collagen fiber bundles of the periodontal ligament, about 3-8 μm in diameter, embedded in the alveolar bone matrix, which were bound encircling the bone matrix fibrils on the bone surface. Type B: fiber bundles about 0.3-1 pm in diameter, which were combined together on the alveolar bone surface. The Type A fibers were observed mainly on the deposition side of the alveolar bone; the Type B fibers were observed on the resorptive side. These two types of collagen fibril components suggest that they are related to tooth movement.
